void interp_one_q(double *uf, double *uc, int nf)

{
  int ic,jc,icc,jcc,nc;
    nc=(nf+1)/2.0;
    //odd-number
    for (ic=1,jc=1;ic<=nc;ic++,jc+=2)
      uf[jc]=uc[ic];
    //even-number
    for (icc=2,jcc=3;icc<nc;icc+=2,jcc+=4){
         uf[jcc-1]=0.375*uc[icc-1]+0.75*uc[icc]-0.125*uc[icc+1];
      uf[jcc+1]=-0.125*uc[icc-1]+0.75*uc[icc]+0.375*uc[icc+1];
   }
}
